circuit-static-description 0.1.8

A boolean gate circuit description package for saving, loading, and evaluating logic circuits.

circuit-static-description

A boolean gate circuit description package with compact binary files and a readable legacy text format.

Installation

Install from PyPI:

pip install circuit-static-description

Python package usage

This project provides a Python package named circuit_static_description. The package supports saving circuits, loading circuits, and evaluating outputs.

Importing

from circuit_static_description import Circuit

Circuit file formats

Circuit files can be saved in two formats:

• Binary format, the default for Circuit.save(...). It stores the parsed expression tree using a compact opcode and varuint encoding, so loading avoids reparsing text expressions.
• Text format, kept for compatibility and readability. Old text files continue to load normally.

Circuit.load(...) automatically detects binary files by their file header. If the header is not present, it reads the file as UTF-8 text.

The text description contains the number of inputs, the number of outputs, optional intermediate variables, and the expression for each output.

• Text comments start with #. The parser ignores everything from # to the end of the line, so comments may appear on their own line or after a definition.
• Input references use I0, I1, I2, etc.
• Intermediate variables use V0, V1, V2, etc. Only V followed by an integer is accepted as a variable name.
• Variable definitions use V<number> = expression and may reference inputs and earlier or later variables.
• Output lines use fixed names OUT0, OUT1, etc.
• Output definitions may reference inputs, variables, and supported logic operators.
• Boolean literals True and False are accepted anywhere an expression is accepted. Literal parsing is case-insensitive.
• Supported logic operators: AND, OR, NOT, XOR, NAND, NOR.
• Circular variable dependencies and undefined variable references are rejected when the circuit is loaded or parsed.

Example:

# This is a readable text circuit file.
INPUTS 3
OUTPUTS 2
V0 = AND(I0, I1)
V1 = XOR(V0, I2)
OUT0 = V0
OUT1 = NOR(False, V1)  # trailing comments are allowed

Saving a circuit

from circuit_static_description import Circuit

circuit = Circuit(
    input_count=3,
    output_count=2,
    variables=[
        ("V0", "AND(I0, I1)"),
        ("V1", "XOR(V0, I2)"),
    ],
    outputs=[
        "V0",
        "NOR(I2, V1)",
    ],
)

circuit.save("example.circuit")  # binary by default
circuit.save("example-text.circuit", mode="text")
circuit.save("example-binary.circuit", mode="binary")

save(...) simplifies the circuit before writing by default. Pass simplify=False to preserve the original expression text:

circuit.save("example-text.circuit", mode="text", simplify=False)

You can also simplify manually. simplify() returns a new Circuit and leaves the original object unchanged.

simplified = circuit.simplify()

Simplification folds constant-only logic, applies boolean identities such as AND(True, X) = X and XOR(True, X) = NOT(X), and extracts repeated gate expressions into new intermediate variables. Existing variable names keep their original V<number> names.

Loading a circuit

from circuit_static_description import Circuit

circuit = Circuit.load("example.circuit")

Evaluating a circuit

result = circuit.evaluate([1, 0, 1])
print(result)
# Example output: [0, 0]

By default, evaluate(...) returns all declared outputs in OUT0, OUT1, ... order. You can also request specific outputs or intermediate variables with targets:

values = circuit.evaluate([1, 0, 1], targets=["V0", "OUT1"])
print(values)
# Example output: [0, 0]

targets accepts either one name such as "V0" or a list of names such as ["OUT0", "V1"]. Target names must be OUT<number> or V<number>, and results are returned in the same order as requested.

Notes

• evaluate accepts a list of input values in input order.
• The output is returned as a list of 0 or 1 values.
• Intermediate variables can be read with evaluate(inputs, targets="V0") or mixed with outputs using targets=["OUT0", "V1"].
• Custom variable names are not supported. Intermediate variables must be named V0, V1, V2, etc.
• Old files without variable definitions still load normally.

Benchmarking sequential evaluation

The repository includes a local benchmark script in tests/benchmark.py for measuring sequential Circuit.evaluate(...) performance on random circuits.

The benchmark script uses tqdm to show progress while running evaluation loops.

Run the benchmark from the project root with the Poetry environment active:

python tests/benchmark.py

For a shorter run, use the quick mode:

python tests/benchmark.py --quick

This script is for local testing only and is not included in the published PyPI package.

Benchmark details

• tests/benchmark.py generates a random circuit with input size, output size, and depth.
• It performs a small calibration run first to choose a comfortable workload that should finish in under 5 minutes.
• It reports the sequential evaluation time for the generated circuit.

Example output

Circuit benchmark
Input count: 16, output count: 128, depth: 6
Rounds: 200
Sequential time: 2.1234s